This application relates to accessory air flow for use on an aircraft.
Gas turbine engines typically need a good deal of accessory air. Air is utilized for various purposes such as cooling components on the engine. Also, gas turbine engines utilized on the aircraft also supply air for use in the cabin of the aircraft. All of these applications require relatively high volumes of air.
Historically, a fan drove air into the gas turbine engine. This fan has typically been driven at the same speed as a lower pressure compressor which is downstream of the fan. More recently, a gear reduction has been incorporated between the fan and the low pressure compressor, and in such engines, the fan rotates at a slower speed compared to the low pressure compressor. With such engines, the air available for accessory use is moving at a slower speed than in the past, and there may not be sufficient volume as would be desirable.